Thursday, May 29, 2008

Watson and Kriek's double helix

Clinical geneticist Marjolein Kriek of Leiden University Medical Centre in the Netherlands is now the first woman to have her genome sequenced,joining the likes of biotechnology maverick Craig Venter and DNA-discoverer James Watson.

"It's really amazing to be there with Watson and Venter. I am just some girl from the Netherlands!" Kriek told me.

And now Kriek and her two X-chromosomes. Her sequence will hopefully shed new light X-linked diseases, especially those that are lethal in men. Funnily enough, says Kriek, she was chosen not just for her sex, but also her name.

In English her surname would sound nearly identical to that of Francis Crick, who shared the Nobel Prize with Watson in 1962 for their work on DNA, but died in 2004 before he could have his genome done. "So now we get Watson and Kriek."

The Leiden team will be analysing her genome over the next few months and then making the data publicly available. There will be a few gaps, however, as Kriek asked for a couple of strong genetic markers for some cancers to be removed from the public view.

Not that she, herself is scared of knowing. "It's not as spooky as everyone thinks."Anna Gosline, New Scientist contributor

Tuesday, May 20, 2008

A hybrid human speaks out

I've taken to groaning out loud every time a media outlet runs yet another story on the UK's hybrid embryos debate. At least the newspapers have stopped pasting animal heads onto human bodies, and if newspaper editors can see sense, surely politicians should follow suit.

Clearly not. In fact in the last 24 hours I've guffawed out loud at some of the ridiculous statements coming out of the mouths of those politicians who oppose the creation of hybrid embryos.

"This is ethically wrong and almost certainly medically useless, or if not useless, there is no evidence as yet to substantiate it," said Edward Leigh MP, on BBC News last night.

How many of the extraordinarily useful drugs we take for granted, or cars, aeroplanes and the lights in our homes would have been developed if there was "no evidence to substantiate them" during the early days of the research? Hey ho, we might as well give up developing anything that doesn't already work and go down to the pub then.

Hybrid embryos may well turn out to be a waste of time. Initial efforts suggest that they can be created, but it may not be possible to make them survive long enough to extract the much-prized stem cells from them. But the potential benefits of stem cell research are so great that we must surely try.

Then this morning in The Guardian, Leigh was quoted accusing Ian Gibson MP of "trying to blind us with science." How else is society expected to make judgements about these profoundly important issues?

But at least the "hybrid embryos" debate has finally reached a head. Last night, 336 British MPs voted against the bid to block hybrid embryo research, versus 176 in favour of banning it.

But what has irked me most about this whole debate is the idea that hybrid embryos are so perverse. These embryos contain 99.9% human DNA, and 0.01% animal DNA. Arguably I'm less than 99.9% human myself.

Once you consider the billions of bacteria living in my gut and on my skin, the parasitic worms which may or may not be colonising my intestines, and the fungi causing the itch between my toes, I'm a walking menagerie. In fact, some scientists have estimated that the total number of microbial genes in the human body outnumber human genes by up to 1000 to 1.

And increasing evidence suggests these organisms aren't just casual passengers, but affect how we perceive pain, shape our immune systems, and protect us from infections.

Even aside from our biological passengers, we have to accept that we're all genetic mongrels, having gradually accumulated the same genetic material as millions of fellow creatures, including viruses, bacteria and houseflies, during the course of our evolution. Doubtless this sharing of our genetic heritage with our biological forebears, is what confused Edward Leigh when he declared having been told "by a scientist" that he was "80% mouse" and "30% daffodil". I'm not sure if either is true, but we do share half our DNA with the humble banana!

In fact the "animal" DNA present in hybrid embryos is mitochondrial DNA - which is originally thought to have come from bacteria, which merged with eukaryotic cells some time in our evolutionary history. So in a sense we're simply being reunited with old relatives.

Then there is the fact that these hybrid embryos are never likely to develop into creatures that walk the earth. They will be destroyed several days after their creation. You could argue that it is wrong to create human embryos that are destined for destruction, but then you'd have to oppose this whole area of stem cell research, not just the creation of human-animal hybrids.

Finally, there are many other types of human-animal hybrids that are already being created - mice containing human brain cells, for example - which are not up for debate in parliament. Trials of insulin-producing pig cells which are injected into humans with diabetes have been approved for some time, but the main concern here has been the possible transfer of pig viruses, not the ethics of creating a hybrid.

And if I were to receive an injection of these cells - or an injection of pig brain cells to replace those destroyed by Parkinson's disease, for example - would this make me any less human? Oink if you agree!

Tuesday, April 29, 2008

Son of a clone is born

Good news for cloning researchers: the world's first cloned horse has given birth to a healthy foal. It may go some way towards allaying fears that cloned animals are less healthy than "normal" ones.

The first cloned horse is a female called Prometea, born in 2003. She was produced by a team led by Cesare Galli, director of the Laboratory of Reproductive Technology in Cremona, Italy. On 17 March 2008, she gave birth to a foal called Pegaso (see Photos, left)

Galli's team are understandably pleased that Pegaso has been born, and that he seems to be in good health. Ultimately time will be the best arbiter, though. Dolly died age six, half the average lifespan for a sheep. Horses generally live 25 or 30 years, and Prometea is only now approaching her fifth birthday - so at the risk of seeming pessimistic, there's plenty of time yet for something to go wrong.

Tuesday, April 22, 2008

Test-tube chicken: Let the games begin

How much are you willing to pay for a really good piece of fried chicken? For animal rights group PETA (People for the Ethical Treatment of Animals) the answer is $1 million - if that chicken came from a cruelty-free Petri dish.

Yesterday, PETA, which is also known for making posters of supermodels who'd rather go naked than sport fur, announced the million-dollar prize for "the first successful individual group or company to…produce an in vitro chicken-meat produce that has a taste and texture indistinguishable from real chicken flesh."

The winning entry must also prove commercially viable by 2016 to receive the prize, a tall order considering a recent study presented at the In Vitro Meat Symposium in Norway this month concluded that one major expense of test-tube meat - a nutrient growth soup - needs to come down 2000% in cost to make in vitro meat competitive with the old-fashioned kind.

The contest's other stipulations cast doubt on whether the award is even winnable. For starters, there's no definition of in vitro meat and no requirement that it actually be made of chicken cells. By that standard, I know a vegetarian restaurant in Seattle whose sweet and sour "chicken" might already be eligible.

The winning entry must also be prepared with a recipe for fried "chicken" made with mock meat and yeast extract and rated between "palatable" and "delicious" by PETA judges – presumably vegetarians – and "indistinguishable from real chicken flesh" by a focus group of 10 meat eaters.

This is, of course, assuming that consumers and federal regulators embrace test-tube meats. Reactions against cloned animal meat suggest that the US Department of Agriculture or Food and Drug Administration won't present the only hurdles for would-be tissue culture farmers. Never mind that any test tube meat would likely require genetic tinkering. Normal cells don't grow endlessly in a Petri dish, let alone form drumsticks.

Monday, April 21, 2008

What price, genome?

That's how biotechnology venture capitalist Noubar Afeyan described personal genomics at a BioInnovations Conference last week on the campus of the Massachusetts Institute of Technology in Cambridge.

"I couldn’t get myself to think this was anything but a luxury," he told a mostly suit-and-tie crowd at MIT's Sloan Business School. "To me it's no different then buying a Bentley."

To Afeyan's right sat Jorge Conde, CEO of Knome, Inc., which claims to offer the world's only commercial whole genome sequence, for $350,000. That price tag includes the luxury treatment.

"For that price we will meet them anywhere on the planet," Conde said. After a consultation and blood draw, Knome provides a complete sequence of a client's genome , delivered on a USB drive. The company also includes follow-up consultations that outline the customer's risk of everything from type 2 diabetes to earwax.

Interesting as that information is, your DNA sequence is little more than personal entertainment, Afeyar said. "The question is how much would you pay to read an incredibly interesting book?"

Of course, the costs of getting a genome continue to plummet, and our knowledge about the human genome grows at an astounding clip. But forgive me for being frugal, I'll take the Bentley. In five years, it will be worth a lot more than my genome.

Thursday, January 24, 2008

Synthetic life: watch this space

Chalk up another first for Craig Venter: a completely synthetic bacterial genome. Unveiled online by Science today, researchers at the J. Craig Venter Institute in Rockville, Maryland, have stitched together the entire genome of the human parasite Mycoplasma genitalium from hundreds of fragments of artificial DNA, produced to order by gene-synthesis firms.

But the real test is yet to come: can the researchers perform a "genome transplant" to replace a natural Mycoplasma genome with a synthetic version, using a technique they demonstrated last year with two different Mycoplasma species? If the synthetic genome "boots up" correctly, things will start to get really interesting. Expect many to denigrate Venter for "playing God". Others will complain that, by trying to patent his creations, Venter could create a "Microbesoft"-like monopoly on this new biological frontier. And some of his rivals may sniffily observe that he hasn't really "created" life, as he needed an existing bacterial cell.

Venter, meanwhile, is thinking big by thinking small. His vision for the future of industry is to create bacteria with stripped-down synthetic genomes, smaller than the current versions, into which he will add other genetic circuitry to make all sorts of useful products. He has been talking about "minimal" genomes since the late 1990s, so it has been a long gestation – but to be fair, Venter has been busy in the meantime, sequencing the human genome (his own, mostly), among other projects.

Other "synthetic biologists" have similar goals, but they plan to add synthetic DNA to existing genomes, rather than building the entire thing from scratch. If their approach works better, those Microbesoft predictions will prove wide of the mark. But even if he isn't the next Bill Gates, it is a safe bet that Venter will remain where he loves to be: in the scientific limelight.